Chat with us on WhatsAppCall Learnizo

Chapter 7 · Kerala SSLC Class 10 Maths

Coordinates

Two ways to learn — a crisp formula reference, or a story that makes the maths feel obvious.

Distance formulaSection formulaCentroidArea of triangle
Kerala SSLCClass 10MathsChapter 7 — Coordinates12 min read

A story that builds each formula naturally.

How story mode works

Each scene is a real situation that naturally leads to a formula. Read the story, then tap "The Maths" to see the formula it maps to.

1

The GPS Map — Distance Formula

Aarav is a delivery driver using a GPS map on his phone. He needs to get from the warehouse at grid point A(1, 2) to a customer at B(4, 6). The roads run in a grid, but the app shows the straight-line distance.

Aarav

I know how far east I have to go and how far north — can I just figure out the actual distance?

East distance: 4 − 1 = 3 units. North distance: 6 − 2 = 4 units. Those two legs form a right triangle.

East leg = 4 − 1 = 3

North leg = 6 − 2 = 4

Straight-line distance = √(3² + 4²)

= √(9 + 16)

= √25 = 5

The Pythagoras theorem on the grid gives exactly 5 units. That is all the distance formula is — Pythagoras applied to coordinates.

2

The Bridge Meeting Point — Midpoint and Section Formula

Meera lives at M(0, 0) and her friend Priya lives at P(8, 6). They want to meet exactly halfway — on a bridge over the river that cuts through the map.

Meera

Halfway between us — that's just the average of our positions, right?

Meeting x = (0 + 8)/2 = 4

Meeting y = (0 + 6)/2 = 3

Midpoint = (4, 3)

Later, a third friend Ravi wants to join them. He says he can only walk one-third of the total distance, so he wants the point that splits M→P in ratio 1:2 (he walks 1 part, Priya walks 2 parts from her side).

Section formula (1:2) from M(0,0) to P(8,6):

x = (1×8 + 2×0)/(1+2) = 8/3 ≈ 2.67

y = (1×6 + 2×0)/(1+2) = 6/3 = 2

Ravi's point ≈ (2.67, 2)

The section formula is a generalised midpoint. When m=n=1, it reduces to the midpoint formula.
3

Calculating Land Area — Triangle Area Formula

A surveyor is measuring a triangular plot of land. The three corner pegs are at A(0, 0), B(3, 0), and C(0, 4) on the grid map. She needs the area for the land deed.

Surveyor

I know the coordinates — I don't need to measure sides. There's a direct formula for area from coordinates.

Area = ½|x₁(y₂−y₃) + x₂(y₃−y₁) + x₃(y₁−y₂)|

= ½|0(0−4) + 3(4−0) + 0(0−0)|

= ½|0 + 12 + 0|

= ½ × 12

= 6

The plot is 6 square units. Notice: if the area comes out 0, the three points are on the same straight line (collinear) — a useful check.

The centroid (centre of mass) of the same triangle is G = ((0+3+0)/3, (0+0+4)/3) = (1, 4/3) — the average of all three vertices.

The big picture

Every formula in Chapter 7 is just arithmetic applied to (x, y) pairs. If you can average two numbers and do Pythagoras, you can do the whole chapter.

Q

How far apart are two points?

d = √((x₂−x₁)² + (y₂−y₁)²)

Q

What is the exact middle?

M = ((x₁+x₂)/2, (y₁+y₂)/2)

Q

Where does a ratio divide the segment?

P = ((mx₂+nx₁)/(m+n), (my₂+ny₁)/(m+n))

Q

What is the area of the triangle?

Area = ½|x₁(y₂−y₃)+x₂(y₃−y₁)+x₃(y₁−y₂)|

Want to go deeper?

Our tutors cover the full Kerala SSLC syllabus live, 1-on-1. If Chapter 7 still feels shaky after this, one session usually fixes it.

Book a Free Trial Class